In conventional wireless LANs, user devices such as personal computers and personal digital assistants (PDAs) communicate with access point (AP) devices in accordance with specified standards. One such standard is described in the Institute of Electrical and Electronics Engineers (IEEE) 802.11b standards document, which is incorporated by reference herein. The 802.11b standard supports data rates of up to 11 Mbps in the 2.4 GHz industrial, scientific and medical (ISM) band, using direct sequence spread spectrum (DSSS).
A considerable amount of effort has been directed to increasing the data bandwidth capabilities of wireless LAN standards such as 802.11b. For example, the 802.11a standard has recently been developed, which supports data rates of up to 54 Mbps in the 5 GHz band using orthogonal frequency division multiplexing (OFDM). Another recently-developed standard is 802.11g, which can support data rates of up to 54 Mbps in the 2.4 GHz band, using DSSS for data rates below 20 Mbps, and OFDM for data rates above 20 Mbps. The 802.11a and 802.11g standards documents are also incorporated by reference herein.
A problem associated with the development of the above-noted 802.11a and 802.11g standards is that these standards generally require new transceiver hardware in order to support the higher data rates. For example, the OFDM-based radios used in 802.11a are not interoperable with the DSSS-based radios used in 802.11b. Similarly, although 802.11g is compatible with 802.11b at data rates below 20 Mbps, it requires different hardware to support the higher data rates. Therefore, those users that have already installed 802.11b hardware are unable to avail themselves of higher data rates without replacing that hardware.
Another approach is utilized in the Texas Instruments ACX100 wireless chipset. This chipset supports two different modes of operation, namely an 802.11b-compatible mode which supports data rates of up to 11 Mbps, and an enhanced “turbo” mode which supports data rates of up to 22 Mbps. However, this approach suffers from the same problem as the recently-developed 802.11a and 802.11g standards, in that specialized hardware is required in order to increase the data rate beyond that supported by the 802.11b standard.
Accordingly, a need exists for alternative techniques for increasing the data bandwidth capabilities of wireless LAN processing devices, such as user devices and access points configured in accordance with the 802.11b standard, without requiring replacement of the existing transceiver hardware.